1. Field of the Invention
The present invention relates to an organic electroluminescence (EL) display emitting light with use of an organic EL effect, and a method of manufacturing the same.
2. Description of the Related Art
As the development of information and communication industry is accelerated, display elements with higher performance are demanded. An organic EL element attracting attention as a next-generation display element has advantages of not only a wide viewing angle and excellent contract but also fast response time.
Materials of a light-emitting layer and the like forming the organic EL element are broadly divided into low-molecular materials and high molecular materials. It is generally known that the low-molecular materials exhibit high light emission efficiency and a long lifetime, and in particular, performance of low-molecular materials emitting blue light is high.
Moreover, as a method of forming an organic film of the organic EL element, a film made of a low-molecular material is formed by a dry method such as a vacuum deposition method, and a film made of a high-molecular material is formed by a wet method such as spin coating, ink jetprinting or nozzle coating.
As an example of using such a forming method, for example, as described in Japanese Patent Nos. 4062352 and 3899566, there are disclosed manufacturing methods in which a red light-emitting layer and a green light-emitting layer are formed by an ink jetprinting method and a blue light-emitting layer is formed by evaporation. In the manufacturing method in Japanese Patent Nos. 4062352 and 3899566, the blue light-emitting layer is manufactured with use of a low-molecular material with high practicality by an evaporation method; therefore, the manufacturing cost is low and the possibility of upsizing displays is high.
Moreover, as described in Japanese Unexamined Patent Application Publication No. 2006-140434, there is disclosed a display in which a blue light-emitting layer is formed as a common layer over a red light-emitting layer and a green light-emitting layer. In such a configuration, fine patterning on the blue light-emitting layer is not necessary; therefore, manufacturing steps are reduced.